Recently, Resistive Random Access Memory (ReRAM) has attracted attention as a non-volatile memory device. The ReRAM stores, in a nonvolatile manner, resistance value information of an electrically rewritable variable resistive element, for example, a high resistance state and a low resistance state of the variable resistive element. In such a ReRAM, for example, variable resistance memory cells in which variable resistive elements as storage elements and rectifying elements such as diodes are connected in series are arranged in array at intersections between a plurality of bit lines extending in parallel to a first direction and a plurality of word lines extending in parallel to a second direction perpendicular to the first direction (for example, see Japanese Patent Laid-Open Publication No. 2007-281208). Examples of the variable resistive elements include metal oxides such as NiO, HfO2, ZrO2, Mn3O4, and CO3O4, and compounds having a perovskite-type structure or a spinel structure which can switch the resistance state between a high resistance state and a low resistance state according to control of a voltage value and voltage application time. In the conventional art, a space between the variable resistance memory cells is filled with an insulating layer formed of SiO2.
The variable resistive element has a structure in which a variable resistive layer including the above metal oxides is arranged between two electrodes and performs a forming processing after formation of the variable resistive element to thereby reduce the resistance of the variable resistive layer. At that time, it is considered that a filament path formed of metal is formed between the two electrodes, and the resistance of the variable resistive layer is reduced. Processing of applying current to the variable resistive element in the low resistance state and returning the resistance state to the high resistance state by Joule heating is referred to as a reset processing. Meanwhile, processing of applying voltage to the variable resistive element in the high resistance state and returning the resistance state of the variable resistive element to the low resistance state is referred to as a set processing. The high and low resistance states are created by the reset processing and the set processing, and the resistance value information is stored, whereby the variable resistive element is operated as a memory (for example, see Japanese Patent Laid-Open Publication No. 2009-9657).